Grey M, Schmidt M, Brendel M
Institut für Mikrobiologie, J. W. Goethe-Universitat, Theodor-Stern-Kai 7, Haus 75, D-60590 Frankfurt am Main, Germany.
Curr Genet. 1996 Apr;29(5):437-40.
In an attempt to clone genes involved in resistance to formaldehyde we have screened a genomic library based on the episomal plasmid YEp24 for the ability to increase resistance to formaldehyde in a wild-type strain. In addition to SFA, the gene encoding the formaldehyde dehydrogenase Adh5, an enzyme most potent in formaldehyde de-toxification, we isolated a second plasmid that conferred a less pronounced but significant hyper-resistance to formaldehyde. Its passenger DNA contained the gene ADH1, encoding alcohol dehydrogenase 1 (EC 1.1.1.1), which could be shown to be responsible for the observed hyper-resistance phenotype. Construction of an adh1-0 mutant revealed that yeast lacking a functional ADH1 gene is sensitive to formaldehyde. While glutathione is essential for Adh5-mediated formaldehyde de-toxification, Adh1 reduced formaldehyde best in the absence of this thiol compound. Evidence is presented that formaldehyde is a substrate for Adh1 in vivo and in vitro and that its cellular de-toxification employs a reductive step that may yield methanol.
为了克隆与抗甲醛相关的基因，我们基于附加体质粒YEp24筛选了一个基因组文库，以检测其在野生型菌株中增强抗甲醛能力的作用。除了编码甲醛脱氢酶Adh5（一种在甲醛解毒中最有效的酶）的SFA基因外，我们还分离出了另一种质粒，它赋予了对甲醛较弱但显著的超抗性。其插入的DNA包含编码乙醇脱氢酶1（EC 1.1.1.1）的ADH1基因，该基因可被证明是观察到的超抗性表型的原因。构建adh1-0突变体表明，缺乏功能性ADH1基因的酵母对甲醛敏感。虽然谷胱甘肽对于Adh5介导的甲醛解毒至关重要，但在没有这种硫醇化合物的情况下，Adh1对甲醛的还原效果最佳。有证据表明，甲醛在体内和体外都是Adh1的底物，其细胞解毒过程采用了一个可能产生甲醇的还原步骤。
